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31.
Objective: To describe the anatomic features of the equine trochanteric bursa and to evaluate 4 techniques for bursa centesis. Study Design: Prospective, randomized design. Animals: Equine cadavers (n=2) and 20 live horses. Methods: The trochanteric bursae of 2 equine cadavers were injected with latex to identify the boundaries of the bursae. Four techniques for centesis of the trochanteric bursa were evaluated by attempting to inject dye into both trochanteric bursae of 20 live horses. Techniques included injection of the bursa with the limb‐bearing weight and injection with the limb nonweight bearing and supported on a block, with or without ultrasonographic guidance of the needle. Ultrasonographic guidance of the needle was performed with or without the use of a guide channel attached to the ultrasound probe. Each of the 4 techniques was used to inject 10 bursae. The region of the bursa was dissected after horses were euthanatized to determine the location of the dye. Results: The trochanteric bursa was most successfully injected with the limb positioned caudally with the foot on a block, even though topographic landmarks for centesis were more difficult to identify when the limb was in this position. The highest incidence of success was achieved when the needle was inserted using ultrasonographic guidance with the foot in a Hickman block. Conclusion: Positioning the limb caudally with the foot nonweight bearing and on a block facilitated centesis of the trochanteric bursa.  相似文献   
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Thirty-six new nitro-alcohol derivatives were synthesised. Tested in vitro against Helminthosporium sativum, the compounds had high antifungal activities; the EC50 values varied between 10?2 and 10?6 M , and for the majority of the compounds between 10?4 and 10?6 M . The EC50 values were calculated by probit analysis, except for the compounds with low activity, for which the values were estimated. Interesting relationships between the structure and antifungal action of the compounds were established.  相似文献   
34.
To optimize their growth and survival, plants perceive and respond to ultraviolet-B (UV-B) radiation. However, neither the molecular identity of the UV-B photoreceptor nor the photoperception mechanism is known. Here we show that dimers of the UVR8 protein perceive UV-B, probably by a tryptophan-based mechanism. Absorption of UV-B induces instant monomerization of the photoreceptor and interaction with COP1, the central regulator of light signaling. Thereby this signaling cascade controlled by UVR8 mediates UV-B photomorphogenic responses securing plant acclimation and thus promotes survival in sunlight.  相似文献   
35.
Nemertines are a phylum of carnivorous marine worms that possess a variety of alkaloidal, peptidic or proteinaceous toxins that serve as chemical defenses against potential predators. The hoplonemertines additionally envenomate their prey with a mixture of proboscis alkaloids delivered with the help of a calcareous stylet that punctures the skin of the victim. Anabaseine, the first of these alkaloids to be identified, stimulates a wide variety of animal nicotinic acetylcholine receptors (AChRs), especially the neuromuscular [e.g., α12β1γδ (embryogenic) or α12β1γɛ (adult)] and α7 AChRs that are inhibited by the snake peptide α-bungarotoxin. A synthetic derivative, 3-(2,4-Dimethoxybenzylidene)-Anabaseine (DMXBA; also called GTS-21), improves memory in experimental animals and humans and is currently in clinical trials to determine whether it can ameliorate cognitive problems associated with schizophrenia. Here we summarize present knowledge concerning the chemistry and mechanisms of action of these two substances (anabaseine and DMXBA) on AChRs, especially those found in the mammalian brain.  相似文献   
36.
The aim of this study was to test whether fragmentation or recreational use affect tree regeneration in urban forests, and to quantify these effects. We sampled tree saplings at different distances from edges in spruce (Picea abies) dominated forests, and at different distances from paths that represented different levels of wear. Generalized linear mixed models were used to test our hypotheses. We found that fragmentation favours the regeneration of deciduous trees in urban spruce dominated forests: distance from the edge had a pronounced effect on regeneration, at least up to 80 m into the forests. Saplings of Betula pendula, Populus tremula, other deciduous species and Pinus sylvestris benefited from edge conditions. Betula pubescens saplings, however, were most abundant in the interior and small Sorbus aucuparia saplings at 25–30 m from the edge. All species suffered from the direct effects of trampling, while varying responses of species to distance from the paths were observed up to 6 m, and possibly further. As trees essentially define the living conditions for other forest species, we suggest that the spatial extent of edge and trampling effects should be studied for different types of forests. This knowledge should then be used in urban forestry and planning to define the threshold value that will allow for at least some “intact” interior. We suggest a diameter larger than 160 m to support indigenous species in boreal spruce dominated forests.  相似文献   
37.
Vitamin C, B5, and B6 contents of potato tubers were measured by gas chromatography‐mass spectrometry (GC‐MS). Two diploid potato populations derived from two different crosses were analyzed. Plants were grown at two locations under different environmental conditions. Measurements of vitamin content of tubers showed high variation in both populations. A weak correlation was found between the vitamin concentrations of tubers harvested at the two locations. Correlations between the mean values of vitamins in field‐grown tubers and in different tissues derived from in vitro or greenhouse‐grown potato plants were also determined. A very high correlation between the vitamin content of field‐ and greenhouse‐grown tubers, and between field‐grown tubers and sink leaves of greenhouse‐grown plants was detected. This finding can facilitate breeding by preselection of individuals with improved vitamin content under greenhouse conditions at their early developmental stage.  相似文献   
38.
The aim of the present study was to clarify the relationship between hypothalamic dopamine (DA) and salsolinol (SAL) for the secretion of prolactin (PRL) in goats. SAL or thyrotropin‐releasing hormone (TRH) was intravenously injected into female goats treated with or without the D2 DA receptor antagonist haloperidol (Hal), which crosses the blood‐brain barrier, and the PRL‐releasing response to SAL was compared with that to TRH. PRL‐releasing responses to SAL, Hal, and Hal plus SAL were also examined after a pretreatment to augment central DA using carbidopa (Carbi) and L‐dopa. The PRL‐releasing response to Hal alone was greater than that to SAL or TRH alone. The PRL‐releasing response to Hal plus SAL was similar to that of Hal alone. In contrast, the PRL‐releasing response to Hal plus TRH was greater than that to TRH or Hal alone. The treatment with Carbi plus L‐dopa inhibited SAL‐ and Hal‐induced PRL secretion. The inhibition of the PRL‐releasing response to SAL disappeared when SAL was injected with Hal. These results indicate that the mechanisms underlying the SAL‐induced PRL response differ from those of TRH, and suggest that hypothalamic DA and its synthesis is associated in part with SAL‐induced PRL secretion in goats.  相似文献   
39.
To study the contributions of high-molecular-weight glutenin subunits (HMW-GS) to the gluten macropolymer and dough properties, wheat HMW-GS (x- and y-types) are synthesized in a bacterial expression system. These subunits are then purified and used to supplement dough mixing and extensigraph experiments through dough partial reduction and reoxidation to allow these exogenously added HMW-GS to incorporate into gluten polymers. Detailed results are given for seven mixing and two extension parameters. HMW-GS synthesized in bacteria behaved similarly under these conditions to the same HMW-GS extracted from wheat flour. These experiments initially focused on the HMW-GS of the D-genome of hexaploid wheat encoded at the Glu-D1 locus; e.g. the Dx2, Dx5, Dy10, and Dy12 subunits. Experiments used five different flours and results are shown to be consistent when normalized to results from Dx5. The incorporation of Dx-type subunits into the gluten disulfide bonded network has greater effects on dough parameters than incorporation of Dy-type subunits. When Glu-D1 x- and y-type subunits are incorporated together, there are synergistic effects greater than those with either subunit type alone. This synergistic effect was greatest with approximately equal amounts of Dx- and Dy-type subunits - implying a 1:1 stoichiometric relationship.  相似文献   
40.
Invasive Phytophthora species are responsible for severe tree diseases in many forest ecosystems in Europe. In Hungary, the symptoms were first noted when P. alni infection led to a serious decline and mortality of alder stands in the late 1990s. Between 2001 and 2009, over 300 soilborne Phytophthora isolates were collected from declining broadleaf forests in Hungary, and 10 Phytophthora species identified based on morphological traits and the molecular characteristics of the internally transcribed spacer (ITS) regions of the nuclear ribosomal DNA. The most diverse species spectrum, found in diseased alder stands, included P. gonapodyides, P. gregata, P. inundata, P. lacustris, P. megasperma, P. plurivora, one informally designated taxon: P. taxon hungarica, and one unnamed species P. sp.1. P. cactorum and P. plurivora isolates were prevalent in the soil of a declining eastern black walnut forest, and three species, P. gonapodyides, P. multivora and P. plurivora were recovered from a declining oak stand. More than one ITS-based genotype was identified for four species, including six genotypes for P. gonapodyides, and two each for P. cactorum, P. plurivora and P. inundata. The high genetic diversity of the P. gonapodyides isolates may indicate that the species is indigenous to the region. In contrast, the frequently recovered, widely distributed P. lacustris with a single ITS genotype may represent a recent colonizer. The P. multivora isolates are, to date, the first reported from a European native forest.  相似文献   
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